Work feeding devices for sewing machines



Dec. 25, 1962 G. GUSTIN WORK FEEDING DEVICES FOR SEWING MACHINES 2 Sheets-Sheet 1 Filed June 24, 1960 Inventor 6/01 m/vo GwT/A/ Attorney Filed June 24, 1960 2 sheets-sheet z Inventor By WWW/Wk;

Attorney G. Gus-r m 3,070,051

United States Patent G1 3,070,051 WORK FEEDING DEVICES FOR SEWING MACHINES Giuliano Gustin, Milan, Italy, assignor to Fratelli Borletti S.p.A., Miian, Italy Filed June 24, 1960, Ser. No. 38,657 Claims priority, application Italy .Iune 26, 1959 6 Claims. (Cl. 112-210) The present invention relates to work-feeding devices for sewing machines.

Such a device consists of mechanisms having the following functions, which are fundamental for the cariying out of the feed process in a sewing machine; the raising of the feed member, the movement of the feed are required for the feed of the material, and the release of the means controlling the raising movement.

These mechanisms are mounted in the lower portion of the sewing machine and movement is imparted to them by the main shaft of the machine, through a transmission comprising a serrated belt.

In its essential outline, the device according to the invention is characterised in that two elements for the support of the work-feeding member, one of which is directly secured to the member whereas the other oscil lates on a pivot secured to the control shaft and secured to the work-feeding member through the agency of a shaft carried thereon and upon which is pivoted the first-mentioned support means, bear by means of sliding blocks integral therewith and in a predetermined position of a rotary cam-carrying shaft which is capable of axial sliding, on two opposite cams carried on the said shaft, in such manner as to be initially spaced apart due to the rotation of the cams, with consequent raising of the work-feeding member which is lifted out of the needle plate flush with whose aperture it is mounted, and then again drawn together in such manner as to cause the work-feeding member to descend.

According to the invention, the cams are shaped in such manner as to impart equal and simultaneous thrusts to the two support elements, during the rotation of the cams, but the arrangement of the said elements relative to the work-feeding member is such that they transmit their thrust movement to the work-feeding member from opposite sides thereof, so that the work-feeding member is'raised and lowered parallel with itself, so that its upper toothed surface always remains parallel to the needle plate.

The cam-carrying shaft is mounted for free rotation in a sleeve disposed coaxially with the toothed wheel controlled via the serrated belt by the main shaft of the machine and is connected to the said wheel by means of at least one rod parallel to the axis thereof and connecting the wheel with a disc secured on the shaft.

With this arrangement, the shaft participates in the rotation of the wheel and at the same time can be caused to slide longitudinally when required.

Such sliding movement is controlled by a hand lever disposed transversely of the shaft, pivoted at an intermediate point along its length and secured at its lower end between projecting thrust members carried on the cam-carrying shaft which can thus be axially displaced in one direction or in the opposite direction by the lever.

The axial displacement of the shaft may thus attain a point at which the blocks integral with the work-feeding device support elements are released by the cams and bear on the cylindrical surface of the shaft. The work-feeding member then remains uninterruptedly lowered, the means for controlling the raising movement having been disengaged.

An embodiment of the device according to the inven- 2 tion is illustrated in the accompanying drawings, wherein: FIGURE 1 shows a plan view of the assembly for controlling the disengagement of the means for raising the work-feeding member;

FIGURE 2 is a longitudinal vertical section through the assembly of FIG. 1;

FIGURE 3 shows the release lever;

FIGURE 4 is a front view of the assembly for actuating the work-feeding member;

FIGURE 5 shows a side view of the said assembly of FIG. 4;

FIGURE 6 shows a FIGS. 4 and 5.

The mechanism illustrated in FIGURES 1 to 3 comprises a toothed wheel 1 to which movement is imparted by means of a serrated belt 2 from the main shaft of the machine. In one piece with the wheel 1 is a toothed wheel 3 for connection with the transmission of the loopgripping member (a mechanism which is not shown in the drawings, since it does not form a part of the present invention).

The wheels 1 and 3 rotate freely on a sleeve 4 and transmit their rotational movement to a shaft 8 passing axially through the sleeve and freely rotatable therein, by means of a rod 5 which is carried by the wheels 1, 3 and is in sliding engagement at 6 with a disc 7 secured firmly on the shaft 8. The shaft 8 carries, at its opposite end, cams 9 and 10 (FIG. 6) for raising the work-feeding member. The shaft 8 is supported at the cam end by a bearing 11.

The shaft 8 may be axially displaced without discontinuing its rotary movement. A ring 12 is mounted on the shaft and secured thereto by means of a screw 13. The ring 12, and consequently also the shaft 8, is urged towards the left (in FIG. 2) by the spring 14 and can be maintained in the required axial position by a lever 15, pivoted on a pin 16 and adapted to be moved between two positions by means of a knob 17 external to the casing of the machine.

' In one position of the lever 15, the cams 9 and 10 are, as indicated in FIGURES 4 to 6, maintained in engagement with respective slide projections 18 and 19. In the other position, they are axially displaced to the left of FIG. 6 and removed from the said projections. In this second position, the raising movement no longer acts on the mechanism of the work-feeding member and the latter remains continuously in the lowered position.

The feed movement is imparted by known means causing an arm 20 to oscillate in phase with the lifting movement. The combination of the two movements, which is again obtained with the said of known means, permits movement of the work-feeding member in one direction when projecting from the needle plate in the raised phase, and movement in the opposite direction when in the lowered phase. The known control means, in addition to imparting reciprocating movement in phase with the raising of the said work-feeding device, also permit adjustment of the amplitude of such movements and, where required, reversal thereof.

The main characteristic of this assembly is that it permi-ts the teeth 21 of the work-feeding member 22 to remain perfectly parallel to the needle plate 23 during the raising movement.

This parallelism and the uniformity of the projecting of the teeth from the plate 23 are maintained in all the raised and lowered positions of the work-feeding device, the movement being obtained in the following manner.

Integral with the arm 20 is a fork 24 on the upper end of which there is pivotally mounted through a shaft 25 an intermediate member 26 fixed on the shaft 25 by means of screws 27. A retaining ring 28 abuts the shaft plan view of the assembly of 25 axially. The intermediate member 26 carries a shaft 7 29 fixed thereon by a screw 30 upon which a member 31 carrying the work-feeding member is pivotally mounted.

The work-feeding member 22 is secured by means of a screw 32 to the member 31 having a projection 19 which bears on the lifting cam 10. A projection 18 of the intermediate member 26 bears on the other cam 9. The two cams are phased in such manner that they simultaneously move the two projections towards and away from the shaft 8. This movement operates the work'feeding member 22 in the following manner.

At a pre-determined moment, the cam 9 displaces the projection 18 downwards. This movement causes the intermediate member 26 to rotate about the shaft 25 and this movement raises the shaft 29 and consequently also the right-hand end (FIG. of the member 31.

' Simultaneously, however, the cam It raises the projection 19 and therefore also the left-hand end of the member 31. The combined movements bring about a parallel upward displacement of the member 31 and consequently also of the work-feeding member 22 secured thereto. The lowering movement of the work-feeding device takes place in an analogous manner.

As seen in FIGURES 4 to 6 the pivoting axis of the arm 29, determined by the pivot 33, is laterally displaced (FIG. 5) relatively to the central position of the shaft 25.

Such displacement brings about an error in the raising position which is corrected by adequately shaping the projection 18, as indicated in FIGURE 5, and. by means of appropriate phasing of the cam 9.

In this way, it is possible to achieve parallelism between the needle plate and the teeth of the Work-feeding member in any desired position, even if oscillating shafts are not in kinematically exact positions relatively to each other.

What I claim is:

1. A work-feeding device for a sewing machine including a feed drive arrn mounted for rotational oscillatory movement and carrying with in its movement a feed member for engagement with the work, the feed member being secured directly to a cam-engaging carrier member pivotally attached to a cam-engaging intermediate member which is pivotally mounted on the feed drive arm, and a rotary cam-carrying shaft carrying opposed first and second cams, the cam-carrying shaft being axially movable between two positions in one of which the carrier member and the intermediate member are in engagement with the first and second cams respectively in such a manner that during rotation of the cam-carrying shaft they are first spaced apart with consequent raising of the feed member and then drawn together causing the feed member to descend.

2. A device as claimed in claim 1, wherein the cams are so shaped as to impart, during their rotation, simultaneous and equal thrusts to the two cam-engaging members.

3. A device as claimed in claim 2, wherein the arrangement of the two cam-engaging members relative to the work-feeding member is such that the former transmit to the latter, from opposite sides thereof, the equal and simultaneous thrusts imparted to them by the eifect of the rotation of the cams so that the work-feeding member is raised and lowered parallel to itself, thus remaining constantly with its upper toothed surface parallel to a needle plate for the work to pass over.

4. A device as claimed in claim 1 including further .a lever operatively connected to said cam-carrying shaft to move said shaft between the two positions wherein one of the positions taken up by the lever is such that, when the lever is moved into that position projections integral with the cam-engaging members supporting the work-feeding member no longer bear on the cams but on the cylindrical surface of the shaft, so that the Workfeeding member can no longer be raised.

5. A device as claimed in claim 4, wherein the camcarrying shaft is mounted for free rotation in a sleeve coaxially disposed in a rotatable toothed wheel said camcarrying shaft is connected to said wheel for rotation thereby by means of at least one rod parallel to the axis thereof which is secured on the wheel at one side and engages at the other side in a radial recess in a disc secured on the cam-carrying shaft, said shaft is axially slidable in said sleeve and along said rod by said lever.

6. A work feeding device in a sewing machine comprising a work-feed carrying member having one end rotatably mounted on a shaft, an intermediate member arranged substantially parallel to said carrying member and having one end thereof rotatably mounted on said shaft, a rocking arm having one end pivotally mounted to said machine and carrying said intermediate member, a cam carrying shaft rotatably mounted in said machine having one end thereof adjacent said Work-feed carrying member and intermediate member, and a pair of cams mounted on said one end of said cam-carrying shaft, said cams cooperating with the other ends of said work-feed carrying member and intermediate member respectively.

References Cited in the file of this patent UNITED STATES PATENTS 1,927,489 Clayton Sept. 19, 1933 2,414,652 Liniger Jan. 21, 1947 2,846,965 Herbst Aug. 12, 1958 FOREIGN PATENTS 518,122 Italy Mar. 4, 1955 OTHER REFERENCES German application, Serial No. B29385 (K52a59), printed March 29, 1956. 

